The present invention relates to audio translators for translating spatially correlated signals into a form acceptable by a desired reproduction system or translating a monophonic signal into spatially correlated signals providing localization information without using delay circuit elements.
Since stereophonic signals derived from microphones spaced apart on a stage have different localization information from binaural signals derived from microphones mounted on a dummy head, reproduction of the stereophonic signals on a stereophonic headphone creates an acoustophysiological effect differing from that created by the same signals when the latter is reproduced on spaced apart loudspeakers. To achieve compatibility between stereophonic loudspeaker and binaural headphone systems, it is necessary to translate the input signals into a form acceptable by the reproduction arrangement. Prior art translators which have hitherto been proposed by the inventor for these purposes, however, involve the use of translating circuits whose transfer functions are given by the ratio B/A, where A is the transmission characteristic of an acoustic path from a loudspeaker to a listener's ear and B is the transmission characteristic of a crosstalk path between the speaker and the listener's other ear. Such translating circuits are only realized by delay circuits and filters due primarily to the time difference associated with the difference in acoustic transit time between the two acoustic paths. Since the delay elements tend to add complexity to circuit configuration with the resultant increase in cost, the prior art translators fall short of the ideal. The same situation occurs in a localization network which translates a monophonic signal into spatially correlated signals.